Katy Perry is planning to hold a massive auction to sell off her glitzy stage costumes after undergoing an image makeover.

The I Kissed a Girl star admits she is testing out a demure new look, so she wants to rid herself of all the sparkly outfits which previously defined her pop persona.

Perry, who keeps all her costumes in a California warehouse, insists a clearout is long overdue, telling Britain's Radio 1, "I have a warehouse here in L.A. and I'll probably do an Elton John-type auction. But I am still going to be bringing the bling. You'll see a bit more of a grown-up version of me, which does not equal boring."